Field Journal 7: Reproductive Ecology and Evolution
Start Time: 1:05pm
End Time: 2:40pm
Date: 04/025/21
Location: Centennial Woods, Burlington VT
Weather: 30℉, rainy, and overcast.
Habitat: Wooded area with waterways running through it. The woods had human footpaths, and a mix of coniferous trees, deciduous trees, and shrubs.
Some behaviors that I observed related to nest selection was a female American Robin flitting around the branches of a coniferous tree, possibly inspecting different branch forks that would be ideal for building a nest in. I heard lots of American Robin calls, which I can assume to be territorial reminders. The American Robins that I observed are most likely nesting in evergreens because of how early in the season it is. American Robins have 2-3 clutches of eggs every year. The first clutch is often raised in evergreen trees because they offer the most protection as opposed to deciduous trees and shrubs that have not leafed out yet. I additionally saw a pair of Mallards, one male, and one female. They will probably be nesting on the bank of the small pond that I was walking by. Mallards prefer to nest in places with some cover, so most likely under a shrub or overhanging vegetation.
Mallards have different habitat requirements (a body of water with sufficient food and vegetation on the bank) than an American Robin, who need leafy trees with forked branches to build their nests. Another species I observed was a House Sparrow, which generally prefers to nest in man-made structures or nest boxes. They also will nest in tree cavities. Additionally, American Crows prefer to nest in tall evergreens, and therefore need more middle/old-growth forest stands.
A bird that I observed defending its territory was an American Robin. I believe it was defending a prime piece of territory because there were lots of evergreens, which they prefer to nest in during the colder months of spring. This indicated that this individual was pretty fit because it has to ward off any other robins who may be looking to steal or trespass on its territory. It probably had a sufficient source of food and shelter, and therefore could spend energy defending its territory.
An American Robin builds its nest out of dead grass, twigs, and mud. While grass and twigs are the most common building materials, they also have been known to use feathers, roots, moss, and paper. The nest is built from the inside out. First, a cup of grass and twigs are formed, and then mud is added to the outside. Soft grass is then used to line the inside. American Robins have to go to wooded areas to find twigs and roots, and places with fields/meadows for grass. Additionally, mud can be acquired near waterways or in low-lying areas where water generally collects.
Mini-Activity: For my mini activity I chose to sit by a stream on the edge of Centennial Woods. I heard 3 different bird calls in about 10 minutes. There was a lot of repetition. I think I heard an American Robin calling the most, along with periodic American Crow calls. There was another bird song that I believe to be a house sparrow, but it was so far away that I could not hear it as well. Overall the American Robin was the closest to me and stayed in the same area. The American Crows flew over me while calling to each other.
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